RFR: 8289230: Move PlatformXXX class declarations out of os_xxx.hpp [v4]

[kristylee88]

On Sat, 2 Jul 2022 04:26:48 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> There are only two implementations of these classes (one for windows, and one for posix):
>> 
>> - PlatformEvent
>> - PlatformParker
>> - PlatformMutex
>> - PlatformMonitor
>> - ThreadCrashProtection
>> 
>> Before this PR, these classes are declared in os_xxx.hpp. This causes excessive inclusion of the large header file os.hpp by popular headers such as mutex.hpp, which needs only the declaration of PlatformMutex but not the other stuff in os.hpp
>> 
>> This PR moves the declarations to park_posix.hpp, mutex_posix.hpp, etc.
>> 
>> Note:  ideally, the definition of PlatformParker/PlatformEvent should be moved to park_posix.cpp, and PlatformMutex/PlatformMonitor should be moved to mutex_posix.cpp. However, the definition of these 4 classes are intertwined, so I'll leave them inside os_posix.cpp for now. (Same for the Windows version).
>
> Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
> 
>  - removed unrelated newline change
>  - Merge branch 'master' into 8289230-move-Platform-classes-out-of-os-xxx-hpp
>  - @coleenp comments
>  - fixed comments
>  - fixed windows
>  - Moved PlatformMutex/PlatformMonitor
>  - move-PlatformParker-out-of-os-xxx-hpp
>  - Moved ThreadCrashProtection

Marked as reviewed by kristylee88 at github.com (no known OpenJDK username).

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PR: https://git.openjdk.org/jdk/pull/9303